Cultured Biologix PK Blossom Bloom Booster 2-12-10, 4 lb.PK Blossom (2 12 10) is a powdered supplemental bloom booster designed to be used in conjunction with any of the base fertilizing systems. This PK supplement provides a burst of phosphorus, potassium, and sulfur to provide the necessary elements needed for enhanced blooming and ripening of flowering plants. Use PK Blossom (2 12 10) through the blooming stage of plant growth. Cultured Biologix PK Blossom Fertilizer Benefits: Promotes Phosphorus Uptake